Comment 2 for bug 1492372

We are planning to introduce a 'provider' unit type. This provider unit could specify how content of the provider could be obtained.

As for now, similar behaviour may be achieved by using local jobs and test plan's bootstrap_include field. The local job should wget/curl the file (and process it if necessary), printing out all jobs definitions.
bootstrap_include serves to specify which jobs should run at first (usually those jobs render more jobs, as in this case).